An inverter is a device for inverting the current of the public electric net into a current with different frequency through the connection and disconnection of its semi-conductors. With the help of the inverter inverting the current frequency, for example, the running speed of a motor connected with the inverter may be changed.
The inverter is widely used in the movement control of the escalator. The movement control of the escalator at lest relates to the switch between/among a variety of movement modes like mode of low speed running, mode of waiting with zero speed, mode of high speed running etc. In the prior arts, the aforesaid switch is achieved by additionally providing a separate control device, some contactors and so on. Particularly, the control device is connected with the inverter and the contactors, and the control device may control the open and close of the contactors and the output of the inverter.
The way of achieving the control of the movement of the escalator by separately providing a control device and contactors as mentioned above at least have below disadvantages:
First, since a separate control device is needed, the cost of the whole control system of the escalator increases.
Second, since there is a separate control device, the user has to do some operations like line connections between the control device and the inverter. However, the operations are time-consuming, and sometimes there is a risk of wrong connection. What's more, the user is even required to do some programming work and some other works to initialize the system, which results in the increase of the human cost and obstructs the fast installation of the control system of escalator on the spot.
Third, since the control of the inverter and the contactors is via some related programs done by the user, the response of the control may be not so fast.
Thus, there is a need for providing an escalator control device with its inverter which at least may solve some or all of the problems as mentioned above.